Field of the Invention
The present invention relates to endoprosthetic devices and, more specifically, to a scapular endoprosthetic device for full repair of glenoid defects.
Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Patients suffering from diseases or deformities of the glenoid fossa of the scapula, prior to the instant invention, have very few options for repair. Bone grafts are sometimes utilized, relying on healthy bone (if available) from another area of the patient's body, donated bone from a cadaver, or synthetic bone in certain situations. However, such real bone grafts are limited in usefulness due to the complexities of the shoulder joint, and are problematic with regard to patient reactions to medication, bleeding, post-operative infection, and attendant pain at the harvest and graft sites. Synthetic bone, on the other hand, while reducing the incidence of rejection and post-operative infection, is limited in usefulness as well due to, again, the complexities of the shoulder joint and the physical stresses experienced therein during normal joint operation.
Current glenohumeral repair techniques include hemiarthroplasty (resurfacing or stemmed), total shoulder replacement, or reverse total shoulder replacement. Resurfacing hemiarthroplasty involves resurfacing of the humeral head joint surface with a cap-like prosthesis of highly polished metal. This is a relatively minimal repair, that relies on the existence of adequate cartilage within the glenoid fossa and a generally otherwise healthy humerus. A stemmed hemiarthroplasty involves a prosthetic humeral head joint surface with an intramedullary stem for fixation within the humeral shaft. This type of repair is often necessitated by severe fractures of the humeral head, but requires a relatively healthy glenoid with intact cartilage surface.
Total shoulder replacement, as the name implies, involves replacement of the entire glenohumeral joint and is typically necessitated by severe arthritis, physical damage, or disease action resulting in loss of joint cartilage. In a standard total shoulder replacement a stemmed hemiarthroplasty repair is mated with a glenoid socket prosthetic component to complete the artificial shoulder joint. The glenoid socket component is either cemented or “press-fit” into the bone of the original glenoid fossa. In a reverse total shoulder replacement scenario the socket and ball components of the repair are reversed, such that the socket portion is fixated on the humeral head and the metal ball portion is fixated in the glenoid fossa.
The current repair methods—hemiarthroplasty and total shoulder repair—each require adequate scapular structure for support and fixation. In instances where disease process has deteriorated the scapular structure such that the glenoid fossa and surrounding bone is not viable, existing repair devices and techniques are useless. What is needed is a scapular glenoid fossa replacement device to effect shoulder repair to restore patient function in such instances of scapular deficiency.